2018 1

19th ICMCF The International Congress on Marine

Corrosion and Fouling

An investigation of marine biofilm effects on the roughness

and drag characteristics of surfaces coated with different

sized cuprous oxide particle

Chang Li1, Mehmet Atlar2, Maryam Haroutunian1, Colin Anderson3

1School of Engineering, Newcastle University, UK

2Ocean and Marine Engineering, University of Strathclyde, UK

3American Chemet Corporation, USA

JUNE 24-29, 2018, MELBOURNE, FLORIDA, USA

2018 2

• Frictional resistance may account for 25% to 80% of the

total ship resistance;

• Frictional resistance is directly affected by the surface

condition (e.g. coating, fouling etc.);

• An increase of 5 µm in roughness can lead to a 4%

increase in drag resistance;

• Slime (biofilm) fouling can cause 5%-25% increase in drag

penalties;

• Weed and hard shell fouling can result in at least 40%

increase in drag penalties.

Motivations

2018 3

D50=60μmD50=25μmD50=12μm D50=17μm

• Four different size of cuprous oxide were

selected with D50 (the median size) values of:

Coating preparations

• Binder system for tested antifouling

system was based on the VC17m part-B:

• Mix ratio: 3 (Cu2O):1 (VC17m/B), then sprayed

onto tested panels

• Dry film contains >90% of Cu2O (by weight)

2018 4

Cage tests

2018 5

Coating preparations

660mm

280m

m

600mm

220m

m

2018 6

Optical surface profilometer

PC Control

Unite

Advantages:

• Less damage, specially for

soft fouling organisms;

• Highly scanning accuracy;

• Easy access for various

surface conditions;

• Multiply parameters analysis

3D results plotting.

2018 7

Turbulent flow channel

PC Control

Unite

2018 8

Turbulent flow channel

2018 9

Fouling growth set-up

2018 10

Dynamic Deployment

• North Sea, Northeast England

• 0.3m submergence depth;

• 15% dynamic activities and

85% static conditions;

• Max. speed 22knots

• Temperature: 6.7°C to 15.3°C;

2018 11

Static Deployment

• Hanging 1.5m depth constantly;

• Temperature: 6.7°C;

2018 12

D50=12μm(Clean) D50=17μm(Clean) D50=25μm(Clean) D50=60μm(Clean)

D50=12μm(Fouled) D50=17μm(Fouled) D50=25μm(Fouled) D50=60μm(Fouled)

2018 13

SEM

D50=12μm(Clean) D50=12μm(1.5M)

D50=12μm(4.5M)

With biofilm present

• Surface fully covered with biofilm;

• No individual Cu2O particle can be

recognised;

• Surface microstructure profile has

completely been reformed;

• Surface profile became rougher;

2018 14

D50=17μm(Clean) D50=17μm(1.5M)

D50=17μm(4.5M)

With biofilm present

• Surface fully covered with biofilm;

• No individual Cu2O particle can be

recognised;

• Surface microstructure profile has

completely been reformed;

• Surface profile became rougher;

2018 15

D50=25μm(Clean) D50=25μm(1.5M)

1.5-month

• Mixture of Biofilm and Bacterial

colonies are largely appeared;

• Most of Cu2O particles have been

covered;

2018 16

D50=25μm(Clean) D50=25μm(1.5M)

4.5-month

• Top surface are fully covered with

biofilm

• Microstructure profile has been

obviously changed;

D50=25μm(4.5M)

2018 17

D50=60μm(Clean) D50=60μm(1.5M)

1.5-month

• Bacterial colonies are largely

appeared and settle on the surface;

• Microstructure profile changes very

slightly;

2018 18

D50=60μm(Clean) D50=60μm(1.5M)

D50=60μm(4.5M)

4.5-month

• Cu2O particles were covered with

biofilm

• Microstructure profile has been

obviously varied;

2018 19

Frictional Drag Measurement

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Clean 1.5M 3M 4.5M 6M

Panels Condition

C12 C17 C25 C60

(%)

2018 20

Frictional Drag Measurement

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Clean 1.5M 3M 4.5M 6M

Panels Condition

C12 C17 C25 C60

(%)

2018 21

Summary: Roughness Analyses

• Cuprous oxide can efficiently prevent hard shell fouling rather

than biofilm fouling;

• Turbulent flow channel can provide a very straight forward access

to evaluate the friction drag of different coatings;

• Biofilm can shortly generate and develop on the relative smoother

surface (or with lower microstructure profiles i.e. D50=12µm,

17µm);

• The interaction between biofilm and surface characteristics

(particle size) would take biofilm longer time to fully develop over

a rougher surface (i.e. D50=60µm);

2018 22

NICE SHAVING!!

2018 23

19th ICMCF The International Congress on Marine

Corrosion and Fouling

Thanks for listening

Questions?